Vehicle operating method and system

• US 6,223,846 B1
• Filed: 06/15/1998
• Issued: 05/01/2001
• Est. Priority Date: 06/15/1998
• Status: Expired due to Fees

• Current Assignee: Michael M. Schechter
• Original Assignee: Michael M. Schechter
• Inventors: Schechter, Michael M.
• Primary Examiner(s): VANAMAN, FRANK BENNETT
• Application Number:
  US09/098,010
• Time in Patent Office: 1,051 Days
• Field of Search: 180/165, 180/69.4, 180/69.5, 180/302, 477/37, 477/186, 477/188, 477/189, 477/209, 123/188.2, 123/90.12, 123/65 SP, 123/527, 123/531, 60/712
• US Class Current: 180/165
• CPC Class Codes: B60K 3/00 Arrangement or mounting of steam or gaseous-pressure propulsion units B60K7/00 takes precedence; arrangement or mounting of plural diverse prime-movers for mutual or common propulsion B60K6/00; gaseous-pressure transmission arrangements B60K17/10
• CPC Class Codes: B60K 6/12 by means of a chargeable fluidic accumulator
• CPC Class Codes: B60T 17/02 Arrangements of pumps or compressors, or control devices therefor
• CPC Class Codes: F01B 17/02 Engines
• CPC Class Codes: F01L 13/0005 Deactivating valves
• CPC Class Codes: F01L 13/065 Compression release engine retarders of the "Jacobs Manufacturing" type
• CPC Class Codes: F01L 2013/0094 with switchable clamp for keeping valve open
• CPC Class Codes: F01L 9/10 by fluid means, e.g. hydraulic
• CPC Class Codes: F01L 9/18 Means for increasing the initial opening force on the valve
• CPC Class Codes: F02B 2075/025 two
• CPC Class Codes: F02B 2075/027 four
• CPC Class Codes: F02B 21/00 Engines characterised by air-storage chambers
• CPC Class Codes: F02B 75/02 Engines characterised by their cycles, e.g. six-stroke
• CPC Class Codes: F02D 13/04 using engine as brake
• CPC Class Codes: F02N 9/04 the pressure fluid being generated otherwise, e.g. by compressing air
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

A method and a system for converting kinetic energy of a vehicle and part of energy supplied by its engine into energy of compressed air and using it to assist in vehicle propulsion later. A novel system of valves employing variable valve timing and valve deactivation is used to implement and control a two-way flow of compressed air between the engine and an air-reservoir where air-temperature control is maintained. During operation with compressed-air assist the engine operates both as an air-motor and as an internal combustion engine during each cycle in each cylinder. The engine can selectively and interchangeably operate either as a four-stroke or as a two-stroke internal combustion engine.

Claims

1. A method of operating a wheeled vehicle, said method comprising the steps of:

(a) providing an engine mounted in said vehicle and coupled to at least one vehicle wheel for its propulsion and braking, said engine including;

(1) at least one cylinder,

(2) a cylinder chamber within said at least one cylinder,

(3) a head mounted to said at least one cylinder, and

(4) a piston operatively engaging said at least one cylinder, with the piston to head and cylinder relationship being such that the volume of said cylinder chamber shrinks during a volume decreasing stroke, when said piston moves towards said head, and expands during a volume increasing stroke, when said piston moves away from said head,

(b) providing an air-reservoir means mounted in said vehicle for receiving, storage, and discharge of compressed air,

(c) providing a control means for controlling the operation of said engine and said vehicle in response to driver'"'"'s demands and in accordance with a control program incorporated in said control means,

(d) providing a gas exchange controlling means for selectively, variably, and alternatively connecting said cylinder chamber to outside atmosphere and to said air-reservoir, in timed relation to said engine operation,

(e) providing a fuel delivery means for selectively and variably adding fuel to the air intended for participation in combustion in said engine in timed relation to said engine operation,

(f) providing a means for allowing a vehicle driver to perform vehicle control functions including;

(1) selectively demanding a vehicle braking force,

(2) selectively demanding a vehicle propulsion force,

(3) selectively demanding a change in magnitude of said vehicle braking force, and

(4) selectively demanding a change in magnitude of said vehicle propulsion force,

(g) operating said engine in a compressor mode driven by a vehicle momentum in response to a demand for a vehicle braking force, when said vehicle is in motion and said engine is coupled to said at least one vehicle wheel, by repeatedly performing a two-stroke compressor cycle in said at least one cylinder during which a charge of atmospheric air is received from said outside atmosphere into said cylinder chamber, compressed therein, and substantially displaced into said air-reservoir means for storage therein, whereby energy of the vehicle motion is transformed into energy of compressed air stored in said air-reservoir means, and

(h) operating said engine in a prime mover mode propelling said vehicle in response to a demand for a vehicle propulsion force when there is no concurrent demand for said vehicle braking force, said prime mover mode including;

(I) operating said engine in a mode selected from a variety of propulsion modes comprising;

(1) a first propulsion mode including repeated performance of a hybrid four-stroke cycle in said at least one cylinder, said hybrid four-stroke cycle comprising two power strokes;

a first power stroke including expansion of a compressed-air charge, received from said air-reservoir means, in said cylinder chamber during a first volume increasing stroke, and

a second power stroke including expansion of combustion gas produced as a result of fuel combustion in said cylinder chamber during a second volume increasing stroke,

 

whereby work performed during said first power stroke is added to work performed during said second power stroke, and

(2) a second propulsion mode including operating said engine in a conventional internal combustion mode receiving air from said outside atmosphere, and

(II) changing said engine operation from one propulsion mode to another one selected from said variety of propulsion modes.

2. The method of claim 1 wherein said variety of propulsion modes further includes:

(a) a third propulsion mode including repeated performance of a hybrid two-stroke internal combustion cycle in said at least one cylinder during which a compressed air charge is received into said cylinder chamber from said air-reservoir means and used for combustion during the same cycle, whereby energy of said compressed air charge supplements the energy released in combustion, and

(b) a fourth propulsion mode including repeated performance of a two-stroke air-motor cycle in said at least one cylinder during which a compressed air charge received from said air-reservoir means expands in said cylinder chamber during said volume increasing stroke, whereby said vehicle is propelled without any fuel being consumed.

3. The method of claim 1 further comprising the steps of deactivating said fuel delivery means and deactivating said gas exchange controlling means in response to an absence of said demand for a vehicle braking force and a concurrent absence of said demand for a vehicle propulsion force, whereby no fuel is consumed when said vehicle is not in motion and when said vehicle is coasting.

4. The method of claim 1 further comprising the steps of providing at least one friction brake, and activating said at least one friction brake in response to said demand for a vehicle braking force when said vehicle is not in motion.

5. The method of claim 1 further comprising the steps of providing at least one friction brake, and activating said at least one friction brake when operating said engine in said compressor mode, whereby the braking force produced by said at least one friction brake supplements the braking force produced by said engine.

6. The method of claim 1 further comprising the steps of providing a transmission means for selectively coupling said engine to said at least one vehicle wheel with a variable transmission ratio, and responding to said demand for a change in magnitude of said vehicle braking force by selectively changing said transmission ratio.

7. The method of claim 1 further comprising the steps of providing a transmission means for selectively coupling said engine to said at least one vehicle wheel with a variable transmission ratio, and responding to said demand for a change in magnitude of said vehicle propulsion force by selectively changing said transmission ratio.

8. The method of claim 1 further comprising the steps of:

(a) initiating selective charging of said air-reservoir means with compressed air whenever the pressure in said air-reservoir means drops below a first predetermined level, said selective charging including the step of operating said engine in a compressor mode driven by vehicle momentum from said at least one vehicle wheel, when said vehicle is coasting, by repeatedly performing a two-stroke compressor cycle in said at least one cylinder during which a charge of atmospheric air is received from outside atmosphere into said cylinder chamber, compressed therein, and substantially displaced into said air-reservoir means for storage therein, the combination of the mass of said charge of atmospheric air and the degree of its compression being such that a predetermined amount of net negative work is performed during each cycle, whereby kinetic energy of the coasting vehicle is transformed into energy of compressed air stored in said air-reservoir means, and whereby a predetermined rate of vehicle deceleration is maintained, and

(b) terminating said selective charging of said air-reservoir when the pressure in said air-reservoir means exceeds a second predetermined level, higher than said first predetermined level.

9. The method of claim 1 wherein said variety of propulsion modes further comprises a hybrid propulsion mode including operation of some of the engine cylinders in a two-stroke internal combustion mode, in which a compressed-air charge is received into said some of the engine cylinders and used for combustion during the same cycle, and operation of the rest of the engine cylinders in a compressor mode pumping compressed air in quantity equal to the quantity of compressed air consumed by the cylinders operating in said two-stroke internal combustion mode, whereby the engine cylinders operating in said two-stroke internal combustion mode propel said vehicle and drive the engine cylinders operating in said compressor mode, and whereby duration of such operation is not limited by the supply of air from said air-reservoir means.

10. The method of claim 1 wherein the step of providing said gas exchange controlling means comprises the steps of:

(a) providing at least one engine valve reciprocable between its closed and open positions in a guide provided in said head,

(b) providing a first hydraulic chamber,

(c) providing a valve piston coupled to said at least one engine valve and reciprocable within said first hydraulic chamber, said valve piston dividing said first hydraulic chamber into a first upper volume and a first lower volume, with the valve piston pressure area in said first upper volume being larger than its pressure area in said first lower volume,

(d) providing a second hydraulic chamber,

(e) providing a partition between said first hydraulic chamber and said second hydraulic chamber,

(f) providing an amplifier piston reciprocable within said second hydraulic chamber, said amplifier piston dividing said second hydraulic chamber into a second upper volume and a second lower volume, with the amplifier piston pressure area in said second upper volume being larger than its pressure area in said second lower volume,

(g) providing a rod coupled to or integral with said amplifier piston and protruding from said second lower volume through an opening in said partition into said first upper volume, where it remains in physical contact with said valve piston when said at least one engine valve is in its closed position and during an initial part of its opening stroke, said initial part of the engine valve opening stroke being of such length that a substantial reduction in the pressure in said cylinder chamber can be achieved when opening said at least one engine valve against an in-cylinder pressure,

(h) providing a high-pressure fluid source and a low-pressure fluid source,

(i) providing high-pressure passages and a normally-closed high-pressure valve for selectively connecting said high-pressure fluid source to said first upper volume and said second upper volume,

(j) providing low-pressure passages and a normally-closed low-pressure valve for selectively connecting said low-pressure fluid source to said first upper volume and said second upper volume,

(k) providing high-pressure passages and a high-pressure check valve for connecting said high-pressure fluid source to said first upper volume and said second upper volume, the check valve installation being such that fluid can flow only into said high-pressure fluid source,

(l) providing low-pressure passages and a low-pressure check valve for connecting said low-pressure fluid source to said first upper volume and said second upper volume, the check valve installation being such that fluid can flow only out of said low-pressure fluid source,

(m) providing a high-pressure passage connecting said high-pressure fluid source to said first lower volume,

(n) providing a low-pressure passage connecting said low-pressure fluid source to said second lower volume, and

(o) using said control means to control said high-pressure and low-pressure valves for repeated and variable opening and closing of said at least one engine valve in timed relation to said engine operation, said opening and closing of the engine valve comprising the steps of;

(1) variably opening said high-pressure valve and connecting said high-pressure fluid source to said first upper volume and said second upper volume, whereby the engine valve is accelerated in the direction of its opening by a combined acceleration force generated by hydraulic pressures acting on both said valve piston and said amplifier piston during said initial part of said engine valve opening stroke,

(2) continuing acceleration of the engine valve in the direction of its opening by an acceleration force generated by hydraulic pressures acting on said valve piston,

(3) variably closing said high-pressure valve and flowing fluid from said low-pressure fluid source through said low-pressure check valve into said first upper volume, whereby the engine valve is decelerated by a deceleration force generated by hydraulic pressures acting on said valve piston until the engine valve exhausts its momentum and stops in its open position,

(4) preventing escape of fluid from said first upper volume, whereby the engine valve is maintained in its open position,

(5) variably opening said low-pressure valve and connecting said low-pressure fluid source to said first upper volume and said second upper volume, whereby the engine valve is accelerated in the direction of its closing by an acceleration force generated by hydraulic pressures acting on said valve piston,

(6) variably closing said low-pressure valve and flowing fluid from said first upper volume through said high-pressure check valve into said high-pressure fluid source, whereby the engine valve is decelerated by a deceleration force generated by hydraulic pressures acting on said valve piston until the engine valve exhausts its momentum and stops in its closed position,

(7) using said control means to selectively vary the timings of openings of said high-pressure and low-pressure valves, whereby the timings of the engine valve opening and closing, respectively, are varied, and

(8) using said control means to selectively vary the timings of closings of said high-pressure and low-pressure valves, whereby the stroke of the engine valve is varied,

whereby contribution of said amplifier piston to the initial acceleration force reduces the hydraulic pressure required to open said at least one engine valve against in-cylinder pressure, whereby energy consumption needed for said at least one engine valve operation is reduced, and whereby said at least one engine valve is operated with variable timings of opening and closing and with a variable stroke.

11. The method of claim 10 further comprising the steps of:

(a) providing a latching means for retaining said at least one engine valve in its closed position,

(b) using said latching means to automatically latch said at least one engine valve in its closed position after it completes its closing stroke,

(c) using said latching means to retain said at least one engine valve in its closed position during a time period between the end of its closing stroke and the beginning of its opening stroke, and

(d) using said latching means to automatically unlatch said at least one engine valve before it begins said opening stroke,

whereby no hydraulic force is needed to retain said at least one engine valve in its closed position.

12. The method of claim 11 further including the step of providing a hydraulic means for unlatching said at least one engine valve, said hydraulic means using pressure from said high-pressure fluid source.

13. The method of claim 1 further comprising the steps of:

(a) providing a heating jacket surrounding said air-reservoir means, and

(b) flowing exhaust gas through said heating jacket during operation of said engine, whereby escape of heat from the air in said air-reservoir is prevented.

14. The method of claim 13 further comprising the steps of:

(a) providing a gas flow control valve for controlling flow of exhaust gas through said heating jacket,

(b) providing a temperature sensor for measuring temperature of air inside said air-reservoir means,

(c) providing said control means with information from said temperature sensor and with ability to cooperate with said gas flow control valve to control said flow of exhaust gas through said heating jacket, and

(d) using said control means to control said flow of exhaust gas in a manner which assures that said temperature of air inside said air-reservoir means is maintained within a predetermined range.

15. The method of claim 1 further comprising the steps of:

(a) providing an electric battery and a battery charge sensor for measuring the charge of said electric battery,

(b) providing an air-motor means coupled to an electric generator, said electric generator being electrically connected to said electric battery and supplying it with electric power when driven by said air-motor means,

(c) providing a control valve and an air-duct for selectively and variably connecting said air-reservoir means to said air-motor means,

(d) providing a speed sensor for measuring the speed of said electric generator, and

(e) providing said control means with information from said electric battery charge and speed sensors, and using said control means to control operation of said control valve for periodic recharging of said electric battery, said recharging comprising the steps of;

(1) using said control valve to start operation of said air-motor means by initiating flow of air from said compressed air reservoir means to said air-motor means whenever the battery charge drops below a first predetermined level,

(2) using said control valve to continue said flow of air from said compressed air reservoir means to said air-motor means until the battery charge increases to a second predetermined level,

(3) using said control valve to vary said flow of air in a manner which assures that the speed of said electric generator is maintained within predetermined limits, and

(4) using said control valve to stop operation of said air-motor means by terminating said flow of air from said compressed air reservoir means to said air-motor means when the battery charge exceeds said second predetermined level,

whereby operation of said electric generator takes place only when charging of the battery is needed, and whereby waste of energy for needless electric generator operation is eliminated.

16. The method of claim 1 further including the step of operating said engine with a reduced frequency of cycle repetition relative to the frequency of said engine revolutions by repeating each two-stroke cycle less frequently than once every engine revolution, and repeating each four-stroke cycle less frequently than once every two engine revolutions, while during the in-between-cycles revolutions said gas exchange means and said fuel delivery means are deactivated, whereby work performed during each cycle increases, and whereby efficiency of said engine is improved.

17. The method of claim 2 wherein the step of providing said gas exchange controlling means comprises the steps of:

(a) providing at least one normally-closed intake valve for selectively and variably connecting said cylinder chamber to said outside atmosphere,

(b) providing at least one normally-closed exhaust valve for selectively and variably connecting said cylinder chamber to said outside atmosphere, and

(c) providing at least one normally-closed charging valve for selectively and variably connecting said cylinder chamber to said air-reservoir means.

18. The method of claim 17 wherein the operation of said engine in said compressor mode comprises, during each two-stroke cycle, the steps of:

(a) deactivating said fuel delivery means,

(b) deactivating said at least one exhaust valve,

(c) expanding the residual compressed air during a first part of said volume increasing stroke,

(d) variably opening said at least one intake valve,

(e) receiving air from said outside atmosphere into said cylinder chamber during a second part of said volume increasing stroke,

(f) variably closing said at least one intake valve,

(g) compressing said air in said cylinder chamber during a first part of said volume decreasing stroke,

(h) variably opening said at least one charging valve,

(i) substantially displacing the compressed air from said cylinder chamber into said air-reservoir means during a second part of said volume decreasing stroke, and

(j) variably closing said at least one charging valve.

19. The method of claim 17 wherein the operation of said engine in said first propulsion mode comprises, during each four-stroke cycle, the steps of:

(a) deactivating said at least one intake valve,

(b) variably opening said at least one charging valve,

(c) receiving compressed air into said cylinder chamber from said air-reservoir means during a first part of a first volume increasing stroke,

(d) variably closing said at least one charging valve,

(e) expanding said compressed air in said cylinder chamber during a second part of said first volume increasing stroke,

(f) compressing the air in said cylinder chamber during a first volume decreasing stroke,

(g) adding fuel to said air in said cylinder chamber,

(h) initiating combustion of said fuel in said cylinder chamber, whereby said fuel and said air are converted into a combustion gas,

(i) expanding said combustion gas in said cylinder chamber during a second volume increasing stroke,

(j) variably opening said at least one exhaust valve,

(k) substantially expelling said combustion gas from said cylinder chamber during a first part of a second volume decreasing stroke,

(l) variably closing said at least one exhaust valve, and

(m) trapping the residual combustion gas remaining in said cylinder chamber during a second part of said second volume decreasing stroke,

whereby work performed by said combustion gas during said second volume increasing stroke is supplemented by work performed by said compressed air during said first volume increasing stroke, and whereby trapping said residual combustion gas in said cylinder chamber during said second part of said second volume decreasing stroke contributes to reduction in harmful nitrogen oxide emission.

20. The method of claim 17 wherein the operation of said engine in said third propulsion mode comprises, during each two-stroke cycle, the steps of:

(a) deactivating said at least one intake valve,

(b) variably opening said at least one charging valve,

(c) receiving compressed air into said cylinder chamber from said air-reservoir means during a second part of said volume decreasing stroke,

(d) variably closing said at least one charging valve,

(e) compressing the air and the residual combustion gas in said cylinder chamber during a third part of said volume decreasing stroke,

(f) adding fuel to the mixture of said air and said residual combustion gas in said cylinder chamber,

(g) initiating combustion of said fuel in said cylinder chamber, whereby said fuel and said air are converted into a combustion gas,

(h) expanding said combustion gas in said cylinder chamber during said volume increasing stroke,

(i) variably opening said at least one exhaust valve,

(j) substantially expelling said combustion gas from said cylinder chamber during a first part of said volume decreasing stroke, and

(k) variably closing said at least one exhaust valve,

whereby receiving of said compressed air into said cylinder chamber from said air-reservoir means reduces the amount of compression work required, and whereby the peak torque and the power of said engine increase.

21. The method of claim 17 wherein the operation of said engine in said fourth propulsion mode comprises, during each two-stroke cycle, the steps of:

(a) deactivating said fuel delivery means,

(b) deactivating said at least one exhaust valve,

(c) variably opening said at least one charging valve,

(d) receiving compressed air into said cylinder chamber from said air-reservoir means during a first part of said volume increasing stroke,

(e) variably closing said at least one charging valve,

(f) expanding said compressed air in said cylinder chamber during a second part of said volume increasing stroke,

(g) variably opening said at least one intake valve,

(h) substantially expelling the air from said cylinder chamber during said volume decreasing stroke, and

(i) variably closing said at least one intake valve.

22. The method of claim 17 wherein the operation of said engine in said fourth propulsion mode comprises, during each two-stroke cycle, the steps of:

(a) deactivating said fuel delivery means,

(b) deactivating said at least one intake valve,

(c) variably opening said at least one charging valve,

(d) receiving compressed air into said cylinder chamber from said air-reservoir means during a first part of said volume increasing stroke,

(e) variably closing said at least one charging valve,

(f) expanding said compressed air in said cylinder chamber during a second part of said volume increasing stroke,

(g) variably opening said at least one exhaust valve,

(h) substantially expelling the air from said cylinder chamber during said volume decreasing stroke, and

(i) variably closing said at least one exhaust valve.

23. The method of claim 17 wherein the operation of said engine in said second propulsion mode includes the step of deactivating said charging valve.

24. The method of claim 17 wherein the operation of said engine in said first propulsion mode comprises, during each four-stroke cycle, the steps of:

(a) variably opening said at least one charging valve,

(b) receiving compressed air into said cylinder chamber from said air-reservoir means during a first part of a first volume increasing stroke,

(c) variably closing said at least one charging valve,

(d) expanding said compressed air in said cylinder chamber during a second part of said first volume increasing stroke,

(e) adding fuel to atmospheric air before it enters said cylinder chamber,

(f) variably opening said at least one intake valve,

(g) receiving an air/fuel mixture through the open intake valve into said cylinder chamber during a third part of said first volume increasing stroke, and mixing it there with air previously received through said charging valve,

(h) variably closing said at least one intake valve,

(i) compressing the air/fuel mixture in said cylinder chamber during a first volume decreasing stroke,

(j) initiating combustion of said fuel in said cylinder chamber, whereby said fuel and said air are converted into a combustion gas,

(k) expanding said combustion gas in said cylinder chamber during a second volume increasing stroke,

(l) variably opening said at least one exhaust valve,

(m) substantially expelling said combustion gas from said cylinder chamber during a second volume decreasing stroke, and

(n) variably closing said at least one exhaust valve,

whereby said engine operates with port fuel injection.

25. The method of claim 17 further comprising the step of responding to said demand for a change in magnitude of said vehicle braking force by making changes in at least one parameter selected from a set of parameters controlling the operation of said gas exchange controlling means, said set of parameters including:

(a) timing of opening of said at least one intake valve,

(b) timing of closing of said at least one intake valve,

(c) timing of opening of said at least one charging valve, and

(d) timing of closing of said at least one charging valve,

whereby the net negative work-per-cycle performed in said at least one engine cylinder is changed.

26. The method of claim 17 further comprising the step of responding to said demand for a change in magnitude of said vehicle propulsion force by selectively making changes in at least one parameter selected from a set of parameters controlling operation of said gas exchange controlling means, said set of parameters including:

(a) timing of opening of said at least one intake valve,

(b) timing of closing of said at least one intake valve,

(c) timing of opening of said at least one charging valve,

(d) timing of closing of said at least one charging valve,

(e) timing of opening of said at least one exhaust valve, and

(f) timing of closing of said at least one exhaust valve,

and changing the quantity of fuel added to the air intended for participation in combustion, when operating in any mode involving fuel combustion, whereby the net positive work-per-cycle performed in said at least one engine cylinder is changed.

27. The method of claim 2 further comprising the steps of:

(a) initiating selective charging of said air-reservoir means with compressed air whenever the pressure in said air-reservoir means drops below a first predetermined level, said selective charging including the step of operating said engine partly in a compressor mode and partly in an internal combustion mode driving said compressor mode, said compressor mode pumping compressed air into said air-reservoir means, and

(b) terminating said selective charging of said air-reservoir means when the pressure in said air-reservoir means exceeds a second predetermined level, higher than said first predetermined level.

28. The method of claim 27 wherein the operation of said engine partly in said compressor mode and partly in said internal combustion mode, when said vehicle is in motion, includes operating some of the engine cylinders in said internal combustion mode, and operating the rest of the engine cylinders in said compressor mode pumping compressed air into said air-reservoir means, whereby the engine cylinders operating in said internal combustion mode propel said vehicle and drive the engine cylinders operating in said compressor mode.

29. The method of claim 27 wherein the operation of said engine partly in said compressor mode and partly in said internal combustion mode, when said vehicle is in motion, includes the steps of operating some of the engine cylinders in a two-stroke internal combustion mode, in which a compressed-air charge is received into said some of the engine cylinders and used for combustion during the same cycle, and operating the rest of the engine cylinders in said compressor mode pumping compressed air into said air-reservoir means and into the cylinders operating in said two-stroke internal combustion mode, whereby the engine cylinders operating in said two-stroke internal combustion mode propel said vehicle and drive the engine cylinders operating in said compressor mode, and whereby a fraction of the compressed air pumped by the cylinders operating in said compressor mode is used by the cylinders operating in said two-stroke internal combustion mode, and the balance of said compressed air goes into said air-reservoir means.

30. The method of claim 27 wherein the operation of said engine partly in said compressor mode and partly in said internal combustion mode, when said vehicle is not in motion, includes the steps of uncoupling said engine from said at least one vehicle wheel, operating some of the engine cylinders in said internal combustion mode, and operating the rest of the engine cylinders in said compressor mode pumping compressed air into said air-reservoir means, whereby the engine cylinders operating in said internal combustion mode drive the engine cylinders operating in said compressor mode.

31. The method of claim 27 wherein the step of providing said gas exchange controlling means comprises the steps of:

(a) providing at least one intake valve for selectively and variably connecting said cylinder chamber to said outside atmosphere,

(b) providing at least one exhaust valve for selectively and variably connecting said cylinder chamber to said outside atmosphere, and

(c) providing at least one charging valve for selectively and variably connecting said cylinder chamber to said air-reservoir means.

32. The method of claim 31 wherein the operation of said engine partly in said compressor mode and partly in said internal combustion mode, when said vehicle is in motion, includes repeated performance of a hybrid four-stroke cycle in said at least one cylinder, said hybrid four-stroke cycle comprising the steps of:

(a) variably opening said at least one intake valve,

(b) receiving air from said outside atmosphere into said cylinder chamber during a first volume increasing stroke,

(c) variably closing said at least one intake valve,

(d) compressing said air in said cylinder chamber during a first part of a first volume decreasing stroke,

(e) variably opening said at least one charging valve,

(f) displacing a fraction of the compressed air from said cylinder chamber into said air-reservoir means during a second part of said first volume decreasing stroke,

(g) variably closing said at least one charging valve,

(h) further compressing the air remaining in said cylinder chamber during a third part of said first volume decreasing stroke,

(i) adding fuel to said air in said cylinder chamber,

(j) initiating combustion of said fuel in said cylinder chamber, whereby said fuel and said air are converted into a combustion gas,

(k) expanding said combustion gas in said cylinder chamber during a second volume increasing stroke,

(l) variably opening said at least one exhaust valve,

(m) substantially expelling said combustion gas from said cylinder chamber during a second volume decreasing stroke, and

(n) variably closing said at least one exhaust valve,

whereby said engine operates, during each cycle in each cylinder, partly in an internal combustion mode propelling said vehicle and partly in a compressor mode pumping compressed air into said air-reservoir means, and whereby part of the energy released in combustion is used to propel said vehicle, and another part of that energy is transformed into energy of compressed air stored in said air-reservoir means.

33. The method of claim 31 wherein the operation of said engine partly in said compressor mode and partly in said internal combustion mode, when said vehicle is not in motion, includes uncoupling said engine from said at least one vehicle wheel and repeated performance of a hybrid four stroke cycle, said hybrid four-stroke cycle comprising the steps of:

(a) variably opening said at least one intake valve,

(b) receiving air from said outside atmosphere into said cylinder chamber during a first volume increasing stroke,

(c) variably closing said at least one intake valve,

(d) compressing said air in said cylinder chamber during a first part of a first volume decreasing stroke,

(e) variably opening said at least one charging valve,

(f) displacing a fraction of the compressed air from said cylinder chamber into said air-reservoir means during a second part of said first volume decreasing stroke,

(g) variably closing said at least one charging valve,

(h) further compressing the air remaining in said cylinder chamber during a third part of said first volume decreasing stroke,

(i) adding fuel to said air in said cylinder chamber,

(j) initiating combustion of said fuel in said cylinder chamber, whereby said fuel and said air are converted into a combustion gas,

(k) expanding said combustion gas in said cylinder chamber during a second volume increasing stroke,

(l) variably opening said at least one exhaust valve,

(m) substantially expelling said combustion gas from said cylinder chamber during a second volume decreasing stroke, and

(n) variably closing said at least one exhaust valve,

whereby said engine operates, during each cycle in each cylinder, partly in a compressor mode pumping compressed-air into said air-reservoir means and partly in an internal combustion mode driving said compressor mode, and whereby substantial part of the energy released in combustion is transformed into energy of compressed air stored in said air-reservoir means.

34. The method of claim 2 wherein the step of providing said gas exchange controlling means comprises the steps of:

(a) providing an intake manifold means for accomodating gas flow into or out of said cylinder chamber,

(b) providing at least one normally-closed intake valve for selectively and variably connecting said cylinder chamber to said intake manifold means,

(c) providing an exhaust manifold means for accomodating gas flow out of or into said cylinder chamber,

(d) providing at least one normally-closed exhaust valve for selectively and variably connecting said cylinder chamber to said exhaust manifold means, and

(e) providing a switching means for setting the arrangement of said gas exchange controlling means into a configuration selected from a variety of configurations, and switching said arrangement from one configuration to another in accordance with said program incorporated in said control means, said variety of configurations including;

(1) a first switching configuration wherein said intake manifold means is connected to outside atmosphere and disconnected from said air-reservoir means, and said exhaust manifold means is connected to said air-reservoir means and disconnected from outside atmosphere,

(2) a second switching configuration wherein said intake manifold means is connected to said air-reservoir means and disconnected from outside atmosphere, and said exhaust manifold means is connected to outside atmosphere and disconnected from said air-reservoir means, and

(3) a third switching configuration wherein said intake manifold means and said exhaust manifold means are both connected to outside atmosphere and disconnected from said air-reservoir means.

35. The method of claim 34 wherein the operation of said engine in said compressor mode comprises the step of operating said gas exchange controlling means in said first switching configuration.

36. The method of claim 34 wherein the operation of said engine in said prime mover mode comprises:

(a) operating said gas exchange controlling means in said second switching configuration if said engine operates in said first propulsion mode,

(b) operating said gas exchange controlling means in said third switching configuration if said engine operates in said second propulsion mode,

(c) operating said gas exchange controlling means in said second switching configuration if said engine operates in said third propulsion mode, and

(d) operating said gas exchange controlling means in said second switching configuration if said engine operates in said fourth propulsion mode.

37. The method of claim 34 wherein the operation of said engine in said prime mover mode comprises:

(a) operating said gas exchange controlling means in said second switching configuration if said engine operates in said first propulsion mode,

(b) operating said gas exchange controlling means in said third switching configuration if said engine operates in said second propulsion mode,

(c) operating said gas exchange controlling means in said second switching configuration if said engine operates in said third propulsion mode, and

(d) operating said gas exchange controlling means in said first switching configuration if said engine operates in said fourth propulsion mode, whereby the functions of said intake valve and said exhaust valve are interchanged and said compressed air enters into said at least one cylinder through said exhaust valve and, after expansion, exits through said intake valve, and whereby excessive cooling of the vehicle catalyst is avoided.

38. The method of claim 34 wherein the step of providing said switching means comprises the steps of:

(a) providing a first intake switching valve for selectively connecting said intake manifold means to outside atmosphere,

(b) providing a second intake switching valve for selectively connecting said intake manifold means to said air-reservoir means,

(c) providing a first exhaust switching valve for selectively connecting said exhaust manifold means to outside atmosphere, and

(d) providing a second exhaust switching valve for selectively connecting said exhaust manifold means to said air-reservoir means.

39. The method of claim 35 wherein the operation of said engine in said compressor mode comprises, during each two-stroke cycle, the steps of:

(a) deactivating said fuel delivery means,

(b) expanding the residual compressed air remaining in said cylinder chamber during a first part of said volume increasing stroke,

(c) variably opening said at least one intake valve,

(d) receiving air from said outside atmosphere into said cylinder chamber during a second part of said volume increasing stroke,

(e) variably closing said at least one intake valve,

(f) compressing said air in said cylinder chamber during a first part of said volume decreasing stroke,

(g) variably opening said at least one exhaust valve,

(h) substantially displacing the compressed air from said cylinder chamber into said air-reservoir means during a second part of said volume decreasing stroke, and

(i) variably closing said at least one exhaust valve.

40. The method of claim 36 wherein the operation of said engine in said first propulsion mode comprises, during each four-stroke cycle, the steps of:

(a) variably opening said at least one intake valve,

(b) receiving compressed air into said cylinder chamber from said air-reservoir means during a first part of a first volume increasing stroke,

(c) variably closing said at least one intake valve,

(d) expanding said compressed air in said cylinder chamber during a second part of said first volume increasing stroke,

(e) compressing the air in said cylinder chamber during a first volume decreasing stroke,

(f) adding fuel to said air in said cylinder chamber,

(g) initiating combustion of said fuel in said cylinder chamber, whereby said fuel and said air are converted into a combustion gas,

(h) expanding said combustion gas in said cylinder chamber during a second volume increasing stroke,

(i) variably opening said at least one exhaust valve,

(j) substantially expelling said combustion gas from said cylinder chamber during a first part of a second volume decreasing stroke,

(k) variably closing said at least one exhaust valve, and

(l) trapping the residual combustion gas remaining in said cylinder chamber during a second part of said second volume decreasing stroke,

whereby work performed by said combustion gas during said second volume increasing stroke is supplemented by work performed by said compressed air during said first volume increasing stroke, and whereby trapping said residual combustion gas in said cylinder chamber during said second part of said second volume decreasing stroke contributes to reduction in harmful nitrogen oxide emission.

41. The method of claim 36 wherein the operation of said engine in said third propulsion mode comprises, during each two-stroke cycle, the steps of:

(a) variably opening said at least one intake valve,

(b) receiving compressed air into said cylinder chamber from said air-reservoir means during a second part of said volume decreasing stroke,

(c) variably closing said at least one intake valve,

(d) compressing the air and the residual combustion gas in said cylinder chamber during a third part of said volume decreasing stroke,

(e) adding fuel to the mixture of said air and said residual combustion gas in said cylinder chamber,

(f) initiating combustion of said fuel in said cylinder chamber, whereby said fuel and said air are converted into a combustion gas,

(g) expanding said combustion gas in said cylinder chamber during said volume increasing stroke,

(h) variably opening said at least one exhaust valve,

(i) substantially expelling said combustion gas from said cylinder chamber during a first part of said volume decreasing stroke, and

(j) variably closing said at least one exhaust valve,

whereby receiving of said compressed air into said cylinder chamber from said air-reservoir means reduces the amount of compression work required, and whereby the peak torque and the power of said engine increase.

42. The method of claim 36 wherein the operation of said engine in said fourth propulsion mode comprises, during each two-stroke cycle, the steps of:

(a) deactivating said fuel delivery means,

(b) variably opening said at least one intake valve,

(c) receiving compressed air into said cylinder chamber from said air-reservoir means during a first part of said volume increasing stroke,

(d) variably closing said at least one intake valve,

(e) expanding said compressed air in said cylinder chamber during a second part of said volume increasing stroke,

(f) variably opening said at least one exhaust valve,

(g) substantially expelling the air from said cylinder chamber during said volume decreasing stroke, and

(h) variably closing said at least one exhaust valve.

43. The method of claim 37 wherein the operation of said engine in said fourth propulsion mode comprises, during each two-stroke cycle, the steps of:

(a) deactivating said fuel delivery means,

(b) variably opening said at least one exhaust valve,

(c) receiving compressed air into said cylinder chamber from said air-reservoir means during a first part of said volume increasing stroke,

(d) variably closing said at least one exhaust valve,

(e) expanding said compressed air in said cylinder chamber during a second part of said volume increasing stroke,

(f) variably opening said at least one intake valve,

(g) substantially expelling the air from said cylinder chamber during said volume decreasing stroke, and

(h) variably closing said at least one intake valve,

whereby the functions of said intake valve and said exhaust valve are interchanged and said compressed air enters into said at least one cylinder through said exhaust valve and, after expansion, exits through said intake valve, and whereby excessive cooling of the vehicle catalyst is avoided.

44. The method of claim 2 further comprising the step of using an operational strategy including:

(a) operating said engine in said second propulsion mode when said vehicle is being propelled with a substantially constant speed,

(b) operating said engine in said compressor mode driven by the vehicle momentum and charging said air-reservoir means with compressed air when said vehicle is being decelerated in response to said demand for said vehicle braking force,

(c) operating said engine in said first propulsion mode when said vehicle is being accelerated and the magnitude of the required engine torque does not exceed a predetermined level,

(d) operating said engine in said third propulsion mode when said vehicle is being accelerated and the magnitude of the required engine torque exceeds said predetermined level,

(e) deactivating said gas exchange controlling means and said fuel delivery means when said vehicle is coasting driven by its inertia,

(f) deactivating said gas exchange controlling means and said fuel delivery means when said vehicle stops, and

(g) restarting said engine, after a full stop, by operating it in said fourth propulsion mode.

45. The method of claim 44 further comprising the step of operating said engine in said first propulsion mode when said vehicle is being propelled with a substantially constant speed, following a period of vehicle deceleration and subsequent acceleration during which the energy accumulated in said air-reservoir means during said deceleration was not fully used up during said acceleration.

46. The method of claim 2 further comprising the step of using an operational strategy including:

(a) operating said engine in said second propulsion mode when said vehicle is being propelled with a substantially constant speed,

(b) operating said engine in said compressor mode driven by the vehicle momentum and charging said air-reservoir means with compressed air when said vehicle is being decelerated in response to a demand for said vehicle braking force,

(c) operating said engine in said first propulsion mode when said vehicle is being accelerated and the magnitude of the required engine torque does not exceed a predetermined level,

(d) operating said engine in said third propulsion mode when said vehicle is being accelerated and the magnitude of the required engine torque exceeds said predetermined level,

(e) initiating an auxiliary charging mode of engine operation when the pressure in said air-reservoir means drops below a first predetermined level, the operation in said auxiliary charging mode including the steps of;

(1) operating said engine in a compressor mode driven by vehicle momentum from said at least one vehicle wheel and pumping compressed air into said air-reservoir means when said vehicle is coasting,

(2) operating said engine partly in said compressor mode pumping compressed air into said air-reservoir means, and partly in an internal combustion mode driving said compressor mode during vehicle stops, and

(3) operating said engine partly in said compressor mode pumping compressed air into said air-reservoir means, and partly in said internal combustion mode driving said compressor mode and propelling said vehicle, when there is a demand for a propulsion force,

(f) continuing operation in said auxiliary charging mode until the pressure in said air-reservoir means rises to a second predetermined level, higher than said first predetermined level,

(g) terminating operation in said auxiliary charging mode when the pressure in said air-reservoir means exceeds said second predetermined level,

(h) deactivating said gas exchange controlling means and said fuel delivery means when said vehicle is coasting driven by its inertia and said engine is not operating in said auxiliary charging mode,

(i) deactivating said gas exchange controlling means and said fuel delivery means when said engine does not operate in said auxiliary charging mode and said vehicle stops, and

(j) restarting said engine after a full stop by operating it in said fourth propulsion mode.

47. A method of operating engine valves, said method comprising the steps of:

(a) providing at least one engine valve reciprocable between its closed and open positions within a head mounted to an engine cylinder,

(b) providing a first hydraulic chamber and a second hydraulic chamber separated from each other by a partition,

(c) providing a valve piston coupled to said at least one engine valve and reciprocable within said first hydraulic chamber, said valve piston dividing said first hydraulic chamber into a first upper volume and a first lower volume,

(d) providing an amplifier piston reciprocable within said second hydraulic chamber, said amplifier piston dividing said second hydraulic chamber into a second upper volume and a second lower volume,

(e) providing a rod coupled to or integral with said amplifier piston and protruding from said second lower volume through an opening in said partition into said first upper volume, where it remains in physical contact with said valve piston when said at least one engine valve is in its closed position and during an initial part of its opening stroke,

(f) providing a high-pressure fluid source and a low-pressure fluid source,

(g) providing a system of valves and conduits for selectively connecting said high-pressure and low-pressure fluid sources to said first and second hydraulic chambers, and for regulating the flow of fluid in the conduits,

(h) providing a control means for control of said system of valves and conduits, and

(i) using said control means for control of said system of valves and conduits to perform a process of repeated and variable opening and closing of said at least one engine valve in timed relation to the engine operation,

whereby contribution of said amplifier piston to the initial acceleration force reduces the hydraulic pressure required to open said at least one engine valve against in-cylinder pressure, and whereby energy consumption needed for the engine valve operation is reduced.

48. The method of claim 47 further comprising the steps of:

(a) providing a latching means for retaining said at least one engine valve in its closed position,

(b) using said latching means to automatically latch said at least one engine valve in its closed position after it completes its closing stroke,

(c) using said latching means to retain said at least one engine valve in its closed position during a time period between the end of its closing stroke and the beginning of its opening stroke, and

(d) using said latching means to automatically unlatch said at least one engine valve before it begins its opening stroke,

whereby no hydraulic force is needed to retain said at least one engine valve in its closed position.

49. The method of claim 48 further including the step of providing a hydraulic means for unlatching said at least one engine valve, said hydraulic means using pressure from said high-pressure fluid source.

50. The method of claim 47 wherein the step of providing said system of valves and conduits comprises the steps of:

(a) providing high-pressure conduits and a normally-closed high-pressure valve for selectively connecting said high-pressure fluid source to said first upper volume and said second upper volume,

(b) providing low-pressure conduits and a normally-closed low-pressure valve for selectively connecting said low-pressure fluid source to said first upper volume and said second upper volume,

(c) providing high-pressure conduits and a high-pressure check valve for connecting said high-pressure fluid source to said first upper volume and said second upper volume, the check valve installation being such that fluid can flow only into said high-pressure fluid source,

(d) providing low-pressure conduits and a low-pressure check valve for connecting said low-pressure fluid source to said first upper volume and said second upper volume, the check valve installation being such that fluid can flow only out of said low-pressure fluid source,

(e) providing a high-pressure conduit connecting said high-pressure fluid source to said first lower volume, and

(f) providing a low-pressure conduit connecting said low-pressure fluid source to said second lower volume.

51. The method of claim 50 wherein the process of opening and closing of said at least one engine valve comprises the steps of:

(a) variably opening said high-pressure valve and connecting said high-pressure fluid source to said first upper volume and said second upper volume, whereby the engine valve is accelerated in the direction of its opening by a combined acceleration force generated by hydraulic pressures acting on both the valve piston and the amplifier piston during said initial part of the engine valve opening stroke,

(b) continuing acceleration of the engine valve in the direction of its opening by an acceleration force generated by hydraulic pressures acting on said valve piston,

(c) variably closing said high-pressure valve and flowing fluid from said low-pressure fluid source through said low-pressure check valve into said first upper volume, whereby the engine valve is decelerated by a deceleration force generated by hydraulic pressures acting on said valve piston until the engine valve exhausts its momentum and stops in its open position,

(d) preventing escape of fluid from said first upper volume, whereby the engine valve is maintained in its open position,

(e) variably opening said low-pressure valve and connecting said low-pressure fluid source to said first upper volume and said second upper volume, whereby the engine valve is accelerated in the direction of its closing by an acceleration force generated by hydraulic pressures acting on said valve piston,

(f) variably closing said low-pressure valve and flowing fluid from said first upper volume through said high-pressure check valve into said high-pressure fluid source, whereby the engine valve is decelerated by a deceleration force generated by hydraulic pressures acting on said valve piston until the engine valve exhausts its momentum and stops in its closed position,

(g) using said control means to selectively vary the timings of openings of the high-pressure and low-pressure valves, whereby the timings of the engine valve opening and closing, respectively, are varied, and

(h) using said control means to selectively vary the timings of closings of the high-pressure and low-pressure valves, whereby the stroke of the engine valve is varied,

whereby contribution of said amplifier piston to the initial acceleration force reduces the hydraulic pressure required to open said at least one engine valve against in-cylinder pressure, whereby energy consumption needed for the engine valve operation is reduced, and whereby said at least one engine valve is operated with variable timings of opening and closing and with a variable stroke.